KR101797785B1 - High-insulating film - Google Patents

Abstract

An object of the present invention is to provide a high insulating film having high electrical properties (dielectric breakdown voltage) and excellent handling properties such as heat resistance, windability and workability.
The present invention relates to a biaxially oriented film comprising a styrenic polymer having a syndiotactic structure as a main constituent, wherein a specific inactive fine particle A, an antioxidant, and a polymer Y having a glass transition temperature Tg of 130 DEG C or higher by DSC, And a refractive index in the thickness direction of 1.5750 or more and 1.6350 or less.

Description

[0001] HIGH-INSULATING FILM [0002]

The present invention relates to a high-insulating film. More particularly, the present invention relates to a high dielectric film having good electrical characteristics and heat resistance, and particularly a high dielectric breakdown voltage.

A film (syndiotactic polystyrene type film) comprising a syndiotactic polystyrene type resin composition is a film excellent in heat resistance, chemical resistance, internal thermal water resistance, dielectric property, electric insulation and the like, Is expected. Particularly, since it has excellent dielectric properties and high electrical insulation and heat resistance, it is expected to be used as an insulator of a capacitor (Patent Documents 1 and 2). For example, Patent Document 3 discloses a technique for improving the withstand voltage by suppressing impurities of the film, Patent Document 4 discloses a technique for improving handling and wear resistance by adjusting additive particles, In documents 5 and 6, techniques for improving the thickness unevenness by adjusting the refractive index of the film are disclosed as techniques of syndiotactic polystyrene-based films used for capacitor applications, respectively. Further, Patent Document 7 discloses a technique for improving an insulation breakdown voltage by adding an antioxidant.

Japanese Patent Application Laid-Open No. Hei 1-182346 Japanese Unexamined Patent Application Publication No. 1-316246 Japanese Patent Application Laid-Open No. 3-124750 Japanese Unexamined Patent Publication No. 6-80793 Japanese Patent Application Laid-Open No. 7-156263 Japanese Patent Application Laid-Open No. 8-283496 Japanese Patent Application Laid-Open No. 2009-235321

However, the syndiotactic polystyrene films disclosed in Patent Documents 1 to 6 are used as an insulator of a capacitor. However, in a capacitor of higher performance such as a capacitor mounted on a recent hybrid car, for example, an insulation breakdown voltage And a film having better electrical properties and heat resistance are required, and the performance may be insufficient. Further, the syndiotactic polystyrene-based film disclosed in Patent Document 7 is preferably used for a capacitor such as a hybrid car, but further improvement of heat resistance and breakdown voltage is required.

For the purpose of improving the capacitance of the capacitor or miniaturizing the capacitor, the film to be an insulator is required to be further thinned, but generally the handling property is lowered as the film is made thinner. Therefore, even if the film is made thinner, a film having better handleability is required, which does not deteriorate the productivity in the film production process and can adapt to the rate of production of a capacitor which is recently required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to provide a highly insulating film excellent in handling properties such as electrical characteristics, heat resistance, windability and workability.

Means for Solving the Problems As a result of diligent studies for solving the above problems, the present inventors have found that, in a syndiotactic polystyrene type biaxially oriented film, a polymer having a specific glass transition temperature is further blended in addition to an antioxidant and specific inert microparticles, The present inventors have found that a highly insulating film having a high dielectric breakdown voltage and excellent heat resistance and handling properties can be obtained.

That is,

1. A biaxially oriented film comprising a styrenic polymer having a syndiotactic structure as a main component, comprising 0.05 to 2.0 mass% of an inert fine particle A having an average particle diameter of 0.05 to 1.5 m and a relative standard deviation of a particle diameter of 0.5 or less By mass or less, an antioxidant in an amount of 0.1% by mass or more and 8% by mass or less, a polymer Y having a glass transition temperature Tg of 130 占 폚 or higher by DSC in an amount of 5% by mass or more and 48% by mass or less and a refractive index in the thickness direction of 1.5750 or more and 1.6350 or less High insulating film.

The present invention also includes the following aspects.

2. The high dielectric constant film according to 1 above, wherein the polymer Y is a polyphenylene ether represented by the following formula (1).

3. The high dielectric constant film according to 1 or 2, wherein the content ratio of the polymer Y to the antioxidant (content of the polymer Y / content of the antioxidant) is 1 to 100.

(1) the peak temperature of the loss elastic modulus (E ") measured at a vibration frequency of 10 Hz by dynamic viscoelasticity measurement is not less than 120 DEG C and not more than 150 DEG C and the dielectric loss tangent (tan?) At 120 DEG C and frequency 1 kHz is 0.0015 or less; To (3).

5. The high dielectric constant film according to any one of 1 to 4 above, wherein the heat shrinkage ratio in the machine direction and the transverse direction at 200 DEG C x 10 minutes is 6% or less.

6. The high dielectric constant film according to any one of items 1 to 5, wherein the dielectric breakdown voltage (BDV) at 120 占 폚 is 350 V / 占 퐉 or more.

7. The high dielectric constant film according to any one of the above items 1 to 6, wherein the storage elastic modulus (E ') at 120 DEG C measured at a vibration frequency of 10 Hz by dynamic viscoelasticity measurement is 600 MPa or more.

8. The high dielectric constant film according to any one of items 1 to 7, wherein the film thickness is 0.4 占 퐉 or more and less than 6.5 占 퐉.

9. An antistatic composition comprising 0.01 to 1.5% by mass of an inert fine particle B having an average particle diameter of not less than 0.5 mu m and not more than 3.0 mu m and having an average particle diameter of not less than 0.2 mu m larger than an average particle diameter of the inert fine particles A, Wherein the high dielectric constant film is a high dielectric constant film.

10. The high dielectric constant film according to any one of items 1 to 9, wherein the inert fine particles A are spherical particles having an aspect ratio of 1.0 or more and 1.3 or less.

11. The high dielectric constant film according to the above 10, wherein the inert fine particles A are spherical polymer resin particles.

(12) The high dielectric constant film according to (10), wherein the inert fine particles (A) are spherical silicone resin particles.

13. The high dielectric constant film according to any one of items 9 to 12, wherein the inert fine particles B are spherical polymer resin particles having an aspect ratio of 1.0 or more and 1.3 or less.

14. The high dielectric constant film according to any one of items 1 to 13 above, wherein the pyrolysis temperature of the antioxidant is 250 占 폚 or higher.

Further, according to the present invention,

15. A capacitor using the high insulating film according to any one of 1 to 14 above.

The high-insulating film of the present invention is a biaxially oriented film mainly composed of a styrene-based polymer described later. Herein, the term " predominant " means that it is more than 50 mass%, preferably not less than 55 mass%, more preferably not less than 60 mass%, particularly preferably not less than 65 mass%, based on the mass of the biaxially stretched film . The high-dielectric film of the present invention contains inert microparticles A, an antioxidant, which will be described later, and a polymer Y having a glass transition temperature Tg of 130 캜 or higher by DSC. Hereinafter, each component constituting the high-insulating film of the present invention will be described.

≪ Styrene-based polymer &

The styrene polymer in the present invention is a styrenic polymer having a syndiotactic structure, that is, a styrene polymer having a steric structure in which a side chain, a phenyl group or a substituted phenyl group is alternately positioned in the opposite direction to a main chain formed of a carbon- will be. In general, tacticity is quantified by nuclear magnetic resonance ( ¹³ C-NMR) method using isotopic carbon, and the ratio of the presence of a plurality of continuous constituent units, for example, 2 for diamond and 3 for tree In the case of five atoms and five atoms, it can be displayed by pentad. In the present invention, the syndiotactic polymer of the syndiotactic structure is preferably at least 75%, preferably at least 85%, or at least 30% in terms of racemic ratios (rrrr) (Poly (alkylstyrene), poly (halogenated styrene), poly (alkoxy styrene), poly (vinyl benzoic acid ester), or hydrogenated polymers obtained by partially hydrogenating these benzene rings, or mixtures thereof, having a syndiotacticity of 50% , Or a copolymer containing these structural units. Examples of the poly (alkylstyrene) include poly (methylstyrene), poly (ethylstyrene), poly (propylstyrene), poly (butylstyrene) Styrene), poly (acenaphthylene), and the like. Examples of the poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like. Examples of the poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferred styrene polymers are polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (pt-butylstyrene) Styrene), poly (p-fluorostyrene), and copolymers of styrene and p-methylstyrene.

When the styrene polymer is used as a copolymer containing a copolymerization component, the comonomer may be an olefin monomer such as ethylene, propylene, butene, hexene, octene, etc., in addition to the monomer of the styrene polymer as described above , Diene monomers such as butadiene and isoprene, and polar vinyl monomers such as cyclic diene monomers, methyl methacrylate, maleic anhydride and acrylonitrile.

The weight-average molecular weight of the styrene-based polymer is preferably 1.0 × 10 ⁴ or more 3.0 × 10 ⁶ or less, more preferably 5.0 × 10 ^4, and more than 1.5 × 10 ^6, particularly preferably at most 1.1 × 10 ⁵ or more 8.0 × 10 ⁵ or less. By setting the weight average molecular weight to 1.0 x 10 ⁴ or more, a film having excellent strength and elongation characteristics and having improved heat resistance can be obtained. When the weight average molecular weight is 3.0 x 10 < ⁶ > or less, the stretching tension is in a preferable range, and breakage or the like does not occur at the time of film production or the like.

Such a method for producing a styrenic polymer having a syndiotactic structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-187708. That is, it is possible to polymerize a styrene-based monomer (a monomer corresponding to the styrene-based polymer) with a condensation product of a titanium compound and water and an organoaluminum compound, particularly trialkyl aluminum, in an inert hydrocarbon solvent or in the absence of a solvent . The poly (halogenated alkylstyrene) is disclosed in JP-A-1-146912, and the hydrogenated polymer is disclosed in JP-A-1-178505.

To the styrenic polymer of the syndiotactic structure in the present invention, an appropriate additive such as antistatic agent known in the art may be added in an appropriate amount. The blending amount thereof is preferably 10 parts by mass or less based on 100 parts by mass of the styrene-based polymer. If the amount is more than 10 parts by mass, it tends to cause fracture at the time of stretching, which is not preferable because the production stability becomes poor.

Such a syndiotactic polymer having a syndiotactic structure is remarkably excellent in heat resistance as compared with a styrene polymer having a conventional atactic structure.

<Antioxidant>

The antioxidant in the present invention may be either a primary antioxidant that captures generated radicals to prevent oxidation or a secondary antioxidant that decomposes the generated peroxide to prevent oxidation. Examples of the primary antioxidant include phenol antioxidants and amine antioxidants, and secondary antioxidants include phosphorus antioxidants and sulfur antioxidants.

Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t- Phenol, 3-t-butyl-4-methoxyphenol, 2,6-di-t- butyl- 4- [4,6- bis (octylthio) -1,3,5-triazin- ] Phenol, and n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate. Further, it is also possible to use 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'- Butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), N, N'-bis [3- (3,5- butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N'-hexane-1,6-diylbis [3- (3,5- ], 3,9-bis [1,1-dimethyl-2- [beta - (3-t-butyl- And oxaspiro [5.5] undecane; and the like. Further, it is also possible to use 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], bis [3,3'-bis - (4-hydroxy-3'-t-butylphenyl) butyryl acid] glycol ester, 1,3,5-tris (3 ', 5'- (1H, 3H, 5H) trione, d-α-tocophenol and the like.

Specific examples of the amine-based antioxidant include alkyl-substituted diphenylamines and the like.

Specific examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis (3-methyl-6-t- Octadecylphosphite, tris (nonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10- (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, ) Phosphite, cyclic neopentane tetraylbis (2,6-di-t-butyl-4-methylphenyl) phosphite, 2,2'-methylenebis (4,6-di- Fights, and the like.

Specific examples of the sulfur-based antioxidant include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropane Pionate, pentaerythritol tetrakis (3-laurylthiopropionate), 2-mercaptobenzimidazole, and the like.

The antioxidant is particularly preferably a primary antioxidant from the viewpoints of more excellent corrosion resistance and an effect of improving the dielectric breakdown voltage. Among them, a phenolic antioxidant is particularly preferable.

The antioxidant preferably has a thermal decomposition temperature of 250 DEG C or higher. If the thermal decomposition temperature is high, the effect of improving the dielectric breakdown voltage at high temperature is high as seen from the examples of the present invention. When the pyrolysis temperature is too low, the antioxidant itself is thermally decomposed at the time of melt extrusion, which tends to cause problems such as contamination of the process or yellowing of the polymer, which is not preferable. From this point of view, the thermal decomposition temperature of the antioxidant is more preferably 280 DEG C or higher, more preferably 300 DEG C or higher, particularly preferably 320 DEG C or higher. The antioxidant in the present invention is preferably not decomposed well and preferably has a high thermal decomposition temperature. However, the upper limit of the antioxidant is practically 500 ° C or less.

The melting point of the antioxidant is preferably 90 ° C or higher. When the melting point is too low, the antioxidant melts faster than the polymer during melt extrusion, and the polymer tends to slip in the screw feed portion of the extruder. This leads to unstable supply of the polymer, resulting in problems such as uneven thickness of the film. From such a viewpoint, the melting point of the antioxidant is more preferably 120 DEG C or higher, more preferably 150 DEG C or higher, particularly preferably 200 DEG C or higher. On the other hand, when the melting point of the antioxidant is too high, the antioxidant tends to be difficult to melt at the time of melt extrusion, and the dispersion in the polymer tends to deteriorate. Thereby, there arises a problem that the effect of addition of the antioxidant is only expressed locally. From this viewpoint, the upper limit of the melting point of the antioxidant is preferably 300 占 폚 or lower, more preferably 250 占 폚 or lower, still more preferably 220 占 폚 or lower, particularly preferably 170 占 폚 or lower.

Commercially available products may be used as such antioxidants as they are. Examples of commercially available products include pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX1010, manufactured by Ciba Specialty Chemicals) (N, N'-hexane-1,6-diisopropylethyl) hydrazine (trade name: IRGANOX1024, manufactured by Ciba Specialty Chemicals Inc.) Di-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide] (trade name: IRGANOX1098, manufactured by Ciba Specialty Chemicals).

The high-insulating film of the present invention contains the antioxidant in an amount of 0.1% by mass or more and 8% by mass or less based on the mass of the high-insulating film. By containing the antioxidant in the above-mentioned content range, the dielectric breakdown voltage is excellent. If the content of the antioxidant is too small, the effect of adding the antioxidant is not sufficient, the dielectric breakdown voltage tends to decrease, and the electrical characteristics become poor. From this viewpoint, the content of the antioxidant is preferably 0.2 mass% or more, more preferably 0.5 mass% or more, and particularly preferably 1 mass% or more. On the other hand, when the content is too large, the antioxidant tends to flocculate in the film, and the defects resulting from the antioxidant tend to increase. Such a defect lowers the dielectric breakdown voltage. From this point of view, the content of the antioxidant is preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

The antioxidant may be used alone or in combination of two or more. Two or more kinds of primary antioxidants may be used, two or more types of secondary antioxidants may be used, and one or more primary antioxidants and one or more secondary antioxidants may be used. An antioxidant may be used in combination. For example, it is expected to prevent both oxidation of primary oxidation and secondary oxidation by using two types of antioxidants, that is, a primary antioxidant and a secondary antioxidant. In the present invention, a mode in which a primary antioxidant is used singly or an aspect in which two or more types of primary antioxidants are used is preferable from the viewpoint that the effect of improving the breakdown voltage can be further enhanced. Based antioxidant is used alone, or two or more phenol-based antioxidants are preferably used.

<Polymer Y>

The polymer Y in the present invention has a glass transition temperature Tg of 130 캜 or higher as determined by DSC (differential scanning calorimeter). It is also preferable that the polymer Y has a Tg higher than the glass transition temperature of the above-mentioned styrene type polymer. When such a polymer Y is blended in the styrene polymer, not only the glass transition temperature Tg as a mixture is increased but also the heat resistance is improved and the breakdown voltage at a high temperature is high as seen from the examples of the present invention. In addition, the thermal stability of the high-insulating film is improved. From this viewpoint, the glass transition temperature Tg of the polymer Y is preferably 150 DEG C or higher, more preferably 180 DEG C or higher, particularly preferably 200 DEG C or higher. The higher the glass transition temperature Tg of the polymer Y to be compounded, the greater the effect of improving the above-mentioned effects such as the stability of the thermal dimensional stability. Considering melt extrusion and the like, the practical upper limit is preferably 350 占 폚, more preferably 300 占 폚.

As such polymer Y, an aromatic polyether, a polycarbonate, a polyallylate, a polysulfone, a polyether sulfone, a polyimide and the like of polyphenylene ether and polyetherimide represented by the following formula (1) can be preferably exemplified . In particular, amorphous polymers are preferred. Among them, polyphenylene ether is particularly preferable because it has a synergistic action with an antioxidant or further improves not only heat resistance and dimensional stability but also breakdown voltage.

The high-insulating film of the present invention is a biaxially oriented film made of a resin composition comprising 5% by mass or more and 48% by mass or less of the above-mentioned polymer Y in the styrene polymer. By mixing the polymer Y in an amount within the above range, the heat resistance and electrical characteristics (breakdown voltage) can be improved, that is, the breakdown voltage at a high temperature can be increased. When the content is too small, heat resistance and electrical characteristics tend to be lowered. From this point of view, the content of the polymer Y is preferably 8% by mass or more, more preferably 11% by mass or more, and particularly preferably 20% by mass or more. When the content is too large, the crystallinity of the styrenic polymer of the syndiotactic structure tends to be lowered, and the heat resistance of the film tends to be lowered. From this viewpoint, the content of the polymer Y is preferably 45 mass% or less, more preferably 40 mass% or less, and particularly preferably 35 mass% or less.

The high dielectric insulating film of the present invention contains the above-mentioned polymer Y and the antioxidant in the respective embodiments as described above, whereby excellent electrical characteristics (dielectric breakdown voltage) and heat resistance can be obtained, that is, The voltage can be made higher.

The content ratio of the polymer Y and the antioxidant (the content of the polymer Y / the content of the antioxidant) is preferably 1 to 100. When the content ratio is in the above-mentioned numerical range, it is particularly excellent in electrical characteristics (dielectric breakdown voltage) and heat resistance. Even if the content ratio is excessively small or excessively large, the effect of further increasing the electrical characteristics and heat resistance tends to be lowered. From this viewpoint, the content ratio is more preferably 3 to 50, and particularly preferably 5 to 30.

<Inert Fine Particle A>

The high dielectric insulating film of the present invention contains an inert fine particle A having a relative standard deviation of an average particle diameter and a particle diameter in a specific numerical range.

The average particle diameter of the inert fine particles A is 0.05 탆 or more and 1.5 탆 or less. By setting the average particle diameter of the inert fine particles A within the above-mentioned numerical range, it is possible to obtain a film with good air releasing property while maintaining a high dielectric breakdown voltage, and to obtain a highly insulating film having excellent windability. If the average particle diameter of the inert fine particles A is excessively small, sufficient air-releasing property tends not to be obtained, resulting in poor windability. From this point of view, the average particle diameter of the inert fine particles A is preferably 0.1 占 퐉 or more, more preferably 0.15 占 퐉 or more, and particularly preferably 0.2 占 퐉 or more. On the other hand, when the average particle diameter is too large, the size of the voids in the film tends to increase, and the dielectric breakdown voltage is lowered. From this viewpoint, the average particle size of the inert fine particles A is preferably 1.0 占 퐉 or less, more preferably 0.6 占 퐉 or less, particularly preferably 0.5 占 퐉 or less.

The relative standard deviation of the particle diameter of the inert fine particles A is 0.5 or less. By setting the relative standard deviation of the particle diameter to the above-mentioned numerical range, the height of the projections on the film surface becomes uniform, and the windability is excellent. In addition, coarse particles and coarse projections are reduced, and the dielectric breakdown voltage is excellent. From this viewpoint, the relative standard deviation of the particle size of the inert fine particles A is preferably 0.4 or less, more preferably 0.3 or less, particularly preferably 0.2 or less.

The inert fine particles A in the present invention are preferably spherical particles having an aspect ratio of 1.0 or more and 1.3 or less. The mouth ratio is more preferably 1.0 or more and 1.2 or less, particularly preferably 1.0 or more and 1.1 or less. When the insertion ratio is in the above numerical range, the effect of improving the winding property and the effect of improving the breakdown voltage can be further enhanced.

The high-insulating film of the present invention contains the above-mentioned inert fine particles A in an amount of 0.05 mass% or more and 2.0 mass% or less in 100 mass% of the high-insulating film. By containing the amount of the inert fine particles A in the above-mentioned numerical range, the handling properties such as the winding-up property of the film can be improved while maintaining a high dielectric breakdown voltage. If the content of the inert fine particles A is too small, the air releasing property tends to be lowered and the windability is deteriorated. From this point of view, the content of the inert fine particles A is preferably 0.1% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.1% by mass or more. On the other hand, when the content is too large, the surface of the film tends to be excessively roughened, thereby deteriorating the scratch resistance of the film surface, and the dielectric breakdown voltage is lowered. In addition, especially in capacitor applications, the space factor tends to increase. From this point of view, the content of the inert fine particles A is preferably 1.0 mass% or less, more preferably 0.5 mass% or less, particularly preferably 0.3 mass% or less.

The inert fine particles A may be organic fine particles or inorganic fine particles.

Examples of the organic fine particles include polymers such as polystyrene resin particles, silicone resin particles, acrylic resin particles, styrene-acrylic resin particles, divinylbenzene-acrylic resin particles, polyester resin particles, polyimide resin particles and melamine resin particles Resin particles. Of these, silicone resin particles and polystyrene resin particles are particularly preferable from the viewpoint of excellent slidability and abrasion resistance. The polymer resin particles are preferably spherical as described above, that is, spherical polymer resin particles are preferable. Of these, spherical silicone resin particles and spherical polystyrene resin particles are particularly preferable from the viewpoint of better slidability and abrasion resistance.

Examples of the inorganic fine particles include (1) silicon dioxide (including hydrates, silica sand, quartz and the like); (2) alumina in various crystal forms; (3) silicates containing 30 mass% or more of the SiO ₂ component (for example, amorphous or crystalline clay minerals, aluminosilicates (including calcined or hydrated), zircon, fly ash and the like); (4) oxides of Mg, Zn, Zr and Ti; (5) sulfates of Ca and Ba; (6) Phosphates of Li, Ba and Ca (including monohydric and dihydrophilic); (7) benzoates of Li, Na and K; (8) terephthalates of Ca, Ba, Zn and Mn; (9) titanates of Mg, Ca, Ba, Zn, Cd, Pb, Sr, Mn, Fe, Co and Ni; (10) chromates of Ba and Pb; (11) carbon (for example, carbon black, graphite and the like); (12) glass (e.g., glass powder, glass beads, etc.); (13) Carbonates of Ca and Mg; (14) fluorspar; (15) spinel-type oxides, and the like. Of these, calcium carbonate particles and silica particles are preferable, and silica particles are particularly preferable from the viewpoint of excellent slidability and abrasion resistance. Such inorganic fine particles are preferably spherical as described above, and spherical silica particles are particularly preferable from the viewpoint of better slidability and abrasion resistance.

Most preferred as the inert fine particles A are spherical silicone resin particles. When spherical silicone resin particles are used as the inert fine particles A, when polyphenylene ether is used as the polymer Y, the heat resistance is particularly high due to the synergistic effect.

<Inert Fine Particles B>

In the high-insulating film of the present invention, it is preferable that, in addition to the inert fine particles A, inert fine particles B having a relative standard deviation of an average particle diameter and a particle diameter are within a specific numerical range.

The average particle diameter of the inert fine particles B is 0.5 mu m or more and 3.0 mu m or less. By setting the average particle diameter of the inert fine particles B to the above-mentioned numerical range, appropriate slipperiness can be obtained and the effect of improving the winding property can be enhanced. When the average particle size of the inert fine particles B is too small, the slidability tends to be lowered, and the effect of improving the winding property is lowered. From this point of view, the average particle diameter of the inert fine particles B is preferably 0.7 μm or more, more preferably 1.0 μm or more, and particularly preferably 1.1 μm or more. On the other hand, when the average particle diameter is too large, the height of the protrusions on the film surface tends to become excessively high, thereby making slippery excessively high, which tends to cause the section deviation at the time of winding. Also, the toughness tends to deteriorate, and the effect of improving the breakdown voltage is lowered. From this viewpoint, the average particle size of the inert fine particles B is preferably 2.0 占 퐉 or less, more preferably 1.5 占 퐉 or less, and particularly preferably 1.3 占 퐉 or less.

The average particle diameter of the inert fine particles B is larger than the average particle diameter of the inert fine particles A by 0.2 m or more. When the difference between the average particle diameter of the inert fine particles A and the average particle diameter of the inert fine particles B is set as described above, the high protrusions (protrusions having a relatively high height) scattered by the inert fine particles B scatter on the surface of the film, The air release performance between the films becomes better. At the same time, a mode in which a low projection due to the inactive fine particle A is present, and the slidability between the films becomes better. As a result, when the film is wound into a roll, it is possible to enhance the effect of improving the winding performance, such as a film roll having a good balance between air-releasing property and slipperiness and having a good wound- From this point of view, the average particle diameter of the inert fine particles B is preferably 0.4 mu m or more larger than the average particle diameter of the inert fine particles A, more preferably 0.6 mu m or more, and particularly preferably 0.8 mu m or more.

The inert microparticle B has a relative standard deviation of the particle diameter of 0.5 or less from the viewpoint of the inert microparticle A described above. The relative standard deviation of the particle size of the inert fine particles B is preferably 0.4 or less, more preferably 0.3 or less, particularly preferably 0.2 or less.

The inert fine particles B are preferably spherical particles having an aspect ratio of 1.0 or more and 1.3 or less, more preferably 1.0 or more and 1.2 or less, and particularly preferably 1.0 or more and 1.1 or less, from the same viewpoint of the inert fine particles A described above.

The high-insulating film of the present invention preferably contains the above-mentioned inert fine particles B in an amount of 0.01 mass% to 1.5 mass% in 100 mass% of the high-insulating film. By containing the amount of the inert fine particles B in the above-mentioned numerical range, it is possible to enhance the handling property such as the winding-up property of the film while maintaining a high dielectric breakdown voltage. When the content of the inert fine particles B is too small, the slidability tends to be lowered, and the effect of improving the winding property is lowered. From this point of view, the content of the inert fine particles B is more preferably 0.05 mass% or more, still more preferably 0.1 mass% or more, particularly preferably 0.2 mass% or more. On the other hand, when the content is excessively large, the frequency of voids in the film tends to increase, and the effect of improving the breakdown voltage is lowered. In addition, the slidability tends to become excessively high, and the section slippage tends to occur at the time of winding, and the effect of improving the winding property is lowered. From this point of view, the content of the inert fine particles B is more preferably 1.0 mass% or less, still more preferably 0.5 mass% or less, particularly preferably 0.4 mass% or less.

As the inert fine particles B, the same organic fine particles and inorganic fine particles as the above-mentioned inert fine particles A can be used. Of these, spherical silicone resin particles and spherical polystyrene resin particles are preferable, and spherical silicone resin particles are particularly preferable from the viewpoints of organic fine particles and excellent slidability and abrasion resistance. Such organic fine particles are preferably spherical as described above, and spherical silicone resin particles are particularly preferable from the viewpoint of better slidability and abrasion resistance. When spherical silicone resin particles are used as the inert fine particles B, when polyphenylene ether is used as the polymer Y, the heat resistance is particularly high due to the synergistic effect.

The inert fine particles A and the inert fine particles B used in the present invention are not limited in their content if they are contained in the final film. For example, there is a method of adding in an optional step of melt extrusion. In order to effectively disperse these fine particles, a dispersant, a surfactant, and the like can be used.

In the present invention, it is preferable to use spherical silicone resin particles in the case of using both of the inert fine particles A and the inert fine particles B. However, even in such a case, the average particle diameters of the respective particles are different , And the relative standard deviation of the particle diameters in the respective particles is small. Therefore, in the particle size distribution curve, the two kinds of particles show two particle diameters that can be clearly distinguished, that is, the inert fine particles A and the inactive fine particles B Can be distinguished clearly. In the case where two grain diameter peaks overlap each other at the slope portion of the gradient to form a valley portion, the grains are divided into two grain diameter peaks with a point indicating a minimum value as a boundary.

<Other additives>

The high-dielectric film of the present invention contains the above-mentioned syndiotactic polymer of the syndiotactic structure, the inert fine particle A, the antioxidant and the polymer Y. In order to further improve the moldability, mechanical properties, And may contain other resin components different from Y.

Examples of other resin components that can be contained include a styrene polymer having an atactic structure, a styrene polymer having an isotactic structure, a styrene-maleic anhydride copolymer, and the like, with a styrenic polymer having the syndiotactic structure The film is easy to be used and is effective for control of crystallization when manufacturing the preform for preliminary molding and can be easily controlled in stretching condition after the film is formed and a film having excellent mechanical properties can be obtained. . Among them, when a styrenic polymer having an atactic structure and / or an isotactic structure is contained, it is preferable that the monomer is composed of the same monomer as the styrenic polymer having a syndyotactic structure. The content of these compatible resin components is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less, based on 100 parts by mass of the styrenic polymer having a syndyotactic structure Or less. If the content of the compatible resin component exceeds 40 parts by mass, the effect of improving the heat resistance, which is an advantage of the styrenic polymer of the syndiotactic structure, is lowered.

Of the other resin components that can be contained, examples of the resin that is non-reactive with the styrenic polymer having a syndyotactic structure include polyolefins such as polyethylene, polypropylene, polybutene, and polypentene, polyethylene terephthalate, Polyester such as polyethylene terephthalate and polyethylene naphthalate, polyamide such as nylon 6 and nylon 6,6, polythioether such as polyphenylene sulfide, polyacrylate, polysulfone, polyether ether ketone, polyether sulfone, Vinyl chloride-based polymers such as Teflon (registered trademark), acrylic polymers such as poly (methyl methacrylate), polyvinyl alcohol, and the like, resins other than the compatibilizing resins are equivalent, and a crosslinking resin . Since these resins are non-flammable with the styrenic polymers of the syndiotactic structure of the present invention, they can be dispersed in the styrenic polymer of the syndiotactic structure in an island form when a small amount is contained, And is effective in improving the slidability of the surface. The content ratio of the incompatible resin component is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less, based on 100 parts by mass of the styrenic polymer having a syndyotactic structure. When the temperature for use as a product is high, it is preferable to contain an incompatible resin component having a relatively high heat resistance.

Additives such as an antistatic agent, a coloring agent, and a lubricant may be added within the range not hindering the object of the present invention.

<Film characteristics>

(Refractive index in the thickness direction)

The high dielectric constant film of the present invention has a refractive index in the thickness direction of 1.5750 or more and 1.6350 or less. By setting the refractive index in the thickness direction to the above-described numerical range, the dielectric breakdown voltage can be increased. In addition, the frequency of film breakage in the film production process is lowered, and productivity can be improved. When the refractive index in the thickness direction is excessively high, the frequency of film breakage tends to increase in the film production process, and the productivity of the film deteriorates. From this point of view, the refractive index in the thickness direction is preferably 1.6200 or less, more preferably 1.6150 or less, particularly preferably 1.6100 or less. On the other hand, when the refractive index in the thickness direction is excessively low, the dielectric breakdown voltage tends to be lowered and the electrical characteristics are lowered. In addition, the frequency of film breakage in the production process of the capacitor is increased, and the productivity of the capacitor is lowered. In addition, the thickness irregularity of the film tends to deteriorate, making it difficult to obtain a capacitor with stable quality. From this point of view, the refractive index in the thickness direction is preferably 1.5800 or more, more preferably 1.5850 or more, particularly preferably 1.5850 or more.

The refractive index in the thickness direction as described above is achieved by employing a manufacturing method described below. That is, the refractive index in the thickness direction preferable in the present invention is a film having a stretching magnification in a specific numerical range to be described later, and in the stretching step, a direction perpendicular to the uniaxial direction The stretching temperature is achieved by dividing the stretching temperature into a plurality of steps and setting a specific temperature difference between the temperature of the first step and the temperature of the last step.

(Film thickness)

The high-insulating film of the present invention preferably has a film thickness of 0.4 mu m or more and less than 6.5 mu m. More preferably not less than 0.4 mu m and not more than 6.0 mu m, and particularly preferably not less than 0.5 mu m and not more than 3.5 mu m. By setting the film thickness to the above-mentioned numerical range, a capacitor having a high capacitance can be obtained.

It is generally well known that a film used as an insulator of a capacitor has a thin film thickness because the capacitance of the capacitor is high. However, if the thickness of the film is actually made thin (thin film), the film tends to be easily wrinkled, or the film tends to be broken. As a result, the handleability is lowered and the added particles tend to fall off. And the absolute value of the dielectric breakdown voltage is lowered due to thinning of the film thickness. Therefore, it is indispensable to balance them. The present invention is to obtain a novel insulating film having a novel constitution comprising an antioxidant, specific particles and a specific polymer so as not to cause the aforementioned problems even if the film thickness is reduced.

(Dielectric breakdown voltage (BDV))

The high dielectric insulating film of the present invention preferably has an insulation breakdown voltage (BDV) at 120 占 폚 of 350 V / 占 퐉 or more. The fact that the dielectric breakdown voltage is in the above-mentioned numerical range means that it has an excellent dielectric breakdown voltage even at a high temperature. The dielectric breakdown voltage is more preferably 400 V / m or more. In order to achieve the dielectric breakdown voltage as described above, the mode of orientation of the film, the polymer Y in the film and the mode of the antioxidant may be defined by the present invention. The dielectric breakdown voltage can also be adjusted by suitably adjusting the shapes of the inactive fine particles A and the inactive fine particles B. It is also effective to set the content ratio of the polymer Y and the antioxidant (the content of the polymer Y / the content of the antioxidant) within a range that the present invention preferably defines. When the amount of the polymer Y or the antioxidant added is decreased, the dielectric breakdown voltage tends to be lowered. Further, when the content of the inactive fine particles A or the inactive fine particles B is increased, the dielectric breakdown voltage tends to be lowered.

The high dielectric insulating film of the present invention preferably has an insulation breakdown voltage at 23 캜 of preferably not less than 400 V / 탆, more preferably not less than 480 V / 탆, . &Lt; / RTI &gt;

(Storage elastic modulus (E '))

The high-dielectric-constant film of the present invention preferably has a storage modulus (E ') of 600 MPa or more at 120 ° C measured at a frequency of 10 Hz by dynamic viscoelasticity measurement. When the storage elastic modulus (E ') at 120 deg. C is in the above-described range, the mechanical properties of the film in a high temperature environment are excellent. When the storage modulus at 120 占 폚 is excessively low, the mechanical properties (breaking strength, elongation at break, etc.) tend to be lowered when used at a high temperature. From this viewpoint, the storage elastic modulus at 120 캜 is more preferably 650 MPa or higher, more preferably 700 MPa or higher, and particularly preferably 750 MPa or higher. In order to achieve the storage elastic modulus (E ') as described above, the embodiment of the polymer Y may be defined by the present invention. When the content of the polymer Y is decreased, the storage elastic modulus (E ') tends to be lowered.

(Loss elastic modulus (E "))

It is preferable that the peak temperature of the loss elastic modulus (E ") measured at a vibration frequency of 10 Hz by dynamic viscoelasticity measurement is 120 deg. C or more and 150 deg. C or less in the high insulating film of the present invention. Properly high temperature means that the temperature at which the molecular motion begins to become active when the high-dielectric film is heated is appropriately high. Therefore, the heat resistance of the film tends to be increased. From this point of view, the peak temperature of the loss elastic modulus (E ") is more preferably at least 125 DEG C, more preferably at least 130 DEG C, and particularly preferably at least 135 DEG C. On the other hand, Is too high, the molecular motion is not easily activated, and the stretching stress tends to occur at the time of the biaxial oriented film production, because the stretching stress at the time of stretching increases. From this viewpoint, the peak temperature of loss elastic modulus (E ") is more preferably 145 DEG C or lower, and further preferably 140 DEG C or lower. To achieve the peak temperature of loss elastic modulus (E & May be appropriately adjusted. More preferably, the content of the polymer Y may be within a range that the present invention preferably defines. It is also effective to set the content ratio of the polymer Y and the antioxidant (the content of the polymer Y / the content of the antioxidant) within a range that the present invention preferably defines. For example, when the content of the polymer Y is increased, the peak temperature of the loss elastic modulus (E ") tends to increase. When the content of the polymer Y is too low, the peak temperature of the loss elastic modulus (E") tends to become excessively low , And it tends to become difficult to reach 120 ° C.

(Dielectric tangent (tan?))

The high dielectric insulating film of the present invention preferably has a dielectric loss tangent (tan?) Of 0.0015 or less at 120 DEG C and a frequency of 1 kHz. When the dielectric loss tangent (tan?) At 120 占 폚 is large, self-heating is liable to occur when the film is used at a high temperature (for example, 120 占 폚) for a long time. From this point of view, the dielectric loss tangent (tan?) At 120 占 폚 is more preferably 0.0012 or less, still more preferably 0.0009 or less, and particularly preferably 0.0006 or less. In order to achieve the dielectric tangent (tan?) As described above, the content of the polymer Y may be appropriately adjusted. More preferably, the content of the polymer Y may be within a range that the present invention preferably defines. It is also effective to set the content ratio of the polymer Y and the antioxidant (the content of the polymer Y / the content of the antioxidant) within a range preferably specified by the present invention. For example, when the content of the polymer Y is reduced, the dielectric tangent (tan?) Tends to be lowered.

(Heat shrinkage ratio)

The high-dielectric-constant film of the present invention preferably has a heat shrinkage ratio of 200 占 폚 占 10 minutes in the machine direction (machine direction) and in the transverse direction (direction perpendicular to the machine axis direction and the thickness direction) of 6% or less. When the heat shrinkage percentage is in the above-mentioned numerical range, it is possible to suppress the blocking caused by the processing (deposition or the like) of the capacitor, and it becomes easy to obtain a capacitor with excellent quality. If the heat shrinkage ratio is too large, blocking tends to occur at the time of processing (vapor deposition or the like) of the capacitor, and it tends to be difficult to obtain good products. From this point of view, the heat shrinkage rate at 200 占 폚 for 10 minutes is more preferably 5% or less, more preferably 4% or less, and particularly preferably 3% or less. In order to achieve the above-described heat shrinkage ratio, the heat-setting temperature may be set within a range described later. If the heat fixing temperature is increased, the heat shrinkage tends to be lowered. In addition, by performing the heat relaxation treatment at the time of opening and closing or the subsequent steps, the numerical range of the heat shrinkage rate can be more effectively achieved.

(Surface roughness)

It is preferable that the center line average surface roughness Ra of at least one surface of the high dielectric insulating film of the present invention is 7 nm or more and 89 nm or less. By setting the center line average surface roughness Ra to the above numerical range, the effect of improving the winding property can be enhanced. Further, the blocking resistance is improved, and the appearance of the roll can be improved. When the centerline average surface roughness Ra is too low, the slidability tends to be excessively low, and the effect of improving the winding performance is low. From this viewpoint, the centerline average surface roughness Ra is preferably 11 nm or more, more preferably 21 nm or more, and particularly preferably 31 nm or more. On the other hand, when the centerline average surface roughness Ra is excessively high, the slidability tends to become excessively high, and therefore, the section slippage tends to occur at the time of winding. From this viewpoint, the center line average surface roughness Ra is more preferably 79 nm or less, further preferably 69 nm or less, particularly preferably 59 nm or less.

In the high-insulating film of the present invention, it is preferable that the ten-point average roughness Rz of at least one surface thereof is 200 nm or more and 3000 nm or less. By setting the ten-point average roughness Rz to the above-described numerical range, the effect of improving the winding property can be enhanced. When the ten-point average roughness Rz is too low, the air-releasing property tends to be lowered when rolled as a roll, and the film tends to slip sideways. Particularly, when the film thickness is thin, since the elasticity of the film is lost, the air releasing property tends to be further lowered, and the effect of improving the winding property is further lowered. From this point of view, the 10-point average roughness Rz is more preferably 600 nm or more, still more preferably 1000 nm or more, particularly preferably 1250 nm or more. On the other hand, when the ten-point average roughness Rz is excessively high, the number of coarse projections tends to increase, and the effect of improving the dielectric breakdown voltage is low. From this point of view, the 10-point average roughness Rz is more preferably 2600 nm or less, still more preferably 2250 nm or less, particularly preferably 1950 nm or less.

Ra and Rz as described above can be achieved by employing the inert fine particles A defined in the present application, and preferably employing the inert fine particles B. [

<Production Method of Film>

The high-insulating film of the present invention can be obtained basically by a method which has been known in the past or has been accumulated in the art, except for some special manufacturing methods. Hereinafter, a production method for obtaining the high-insulating film of the present invention will be described in detail.

First, a resin composition in which a predetermined amount of a polymer Y and an antioxidant are blended with a styrenic polymer having a syndyotactic structure is heated and melted to prepare an unoriented sheet. Specifically, the resin composition is heated and melted at a temperature equal to or higher than the melting point (Tm, unit: 占 폚) or higher (Tm + 50 占 폚) of the resin composition and extruded into a sheet to obtain an unstretched sheet. The intrinsic viscosity of the obtained unoriented sheet is preferably in the range of 0.35 to 0.9 dl / g. Subsequently, this unstretched sheet is stretched in two axes. The stretching may be simultaneous stretching in the longitudinal direction (machine axis direction) and in the transverse direction (the direction perpendicular to the machine axis direction and the thickness direction), or sequentially stretched in an arbitrary order. For example, in the case of continuous stretching, at least 2.7 times or more and 4.8 times or less at a temperature of not less than (Tg + 70 deg. C) or more in the uniaxial direction (glass transition temperature (Tg, unit: Is 2.8 times or more and 4.9 times or less at a temperature equal to or higher than Tg (Tg + 80 DEG C) in a direction perpendicular to the uniaxial direction, and is then stretched at a magnification of 2.9 times or more and 4.4 times or less, more preferably 3.1 times or more and 4.0 times or less. , Preferably 3.0 times or more and 4.5 times or less, more preferably 3.2 times or more and 4.1 times or less.

In addition, at the time of stretching in the direction perpendicular to the uniaxial direction, crystallization is progressing in the stretching of the previous stage or elongation becomes difficult, and breakage tends to occur during the film production. Particularly, in the case of producing a thin film having a film thickness of about 3 占 퐉, breakage tends to occur especially in a region where the stretching magnification is 3.2 times or more.

As a result of studying this measure, it has been found effective to set the stretching speed to a specific numerical value range in the stretching in the direction perpendicular to the uniaxial direction. That is, when the stretching speed is too fast, the change in the higher order structure of the molecules due to stretching can not follow the rate of change in the shape of the film due to stretching, and deformation is likely to occur in the higher order structure. It becomes easy to occur. In view of this, the stretching speed is preferably 30000% / min or less, more preferably 15000% / min or less, still more preferably 9000% / min or less, particularly preferably 6000% / min or less. On the other hand, when the stretching speed is too slow, the film is crystallized in advance during the stretching, and unevenness in stretching and thickness irregularity tend to occur, and breakage tends to occur due to deviation in stretching stress. From this viewpoint, the stretching speed is preferably 500% / min or more, more preferably 1000% / min or more, still more preferably 2000% / min or more, particularly preferably 4000% / min or more.

As another effective means for suppressing the fracture, it is preferable that, in the stretching in the direction perpendicular to the uniaxial direction, the stretching temperature is not made constant but divided into a plurality of steps and the temperature in the first step and the temperature in the final step It is proved that it is effective to set the temperature difference. The temperature difference of the final stage is preferably 4 ° C or more, more preferably 7 ° C or more, more preferably 12 ° C or more, and particularly preferably 15 ° C or more higher than the temperature of the first stage. In addition, when the temperature difference is excessively large, film breakage tends to occur easily. In addition, there is a tendency that the thickness unevenness of the film after stretching is deteriorated. From this viewpoint, the temperature difference is preferably 49 DEG C or lower, more preferably 39 DEG C or lower, more preferably 29 DEG C or lower, and particularly preferably 20 DEG C or lower. Thus, by setting the temperature difference between the first step and the final step within the above-described numerical range, it is possible to achieve a high draw ratio, that is, a high refractive index in the thickness direction, which was conventionally difficult in the production of a thin film. In this way, a film having good thickness irregularity can be obtained.

In order to set the temperature difference between the first stage and the final stage in the step of stretching in the direction perpendicular to the uniaxial direction, the temperature difference between the inlet (first stage) and the outlet (final stage) Or two or more continuous stretching zones having different temperatures may be formed and the temperature difference may be set between the first stretching zone (first stage) and the last stretching zone (final stage). The term &quot; zone &quot; refers to a region of 1 divided by a shutter or the like in a tenter or the like. In either case, it is preferable to further divide the first stage and the final stage so that the temperature is gradually increased toward the final stage in the first stage, and particularly, it is required to increase linearly. For example, when two or more continuous stretching zones having different temperatures are used, it is preferable to form one or more stretching zones further between the first stretching zone and the last stretching zone, Is more preferable. It is disadvantageous in terms of facility cost that the sum of the stretching zones is 11 or more. In the stretching, for example, when the film is stretched in the width direction, it is sufficient that the value obtained by dividing the film width immediately after leaving the final step by the film width immediately before entering the first step is the target stretching magnification, It is preferable to increase the film width, particularly, to increase linearly. Even when the longitudinal direction and the transverse direction are simultaneously stretched, the stretching temperature is similarly divided into a plurality of steps, and the temperature difference is set between the temperature of the first step and the temperature of the final step.

In the present invention, these means can be preferably exemplified as a means for achieving the preferable refractive index in the thickness direction in the present invention. By employing these means, since the film is not easily broken even if the film thickness is reduced, these means can be exemplified as preferable means for achieving the preferable film thickness in the present invention. In the present invention, it is preferable to employ at least any one of the above-described modes of stretching speed and the stretching temperature, but it is more preferable to use both of them, and the stretching process is stabilized, It becomes easy to achieve the desired refractive index and the desired film thickness in the film.

Then, heat-set at a temperature of (Tg + 70 deg. C) to Tm. The temperature of the open and defined temperature is not less than 200 ° C and not more than 260 ° C, preferably not less than 220 ° C and not more than 250 ° C, more preferably not less than 230 ° C and not more than 240 ° C. When the heat fixing temperature is too high, film breakage tends to occur particularly when a film having a small film thickness is produced, and the thickness irregularity deteriorates. After the heat is fixed, if necessary, relaxation treatment is performed at a temperature lower than the heat fixing temperature by 20 占 폚 to 90 占 폚 to improve the dimensional stability.

The high-insulating film of the present invention may have a coating layer on one side or both sides of the film as a preferred embodiment. The surface energy of such a coating layer is preferably smaller than the surface energy of the film. By providing such a coating layer, the coating layer covers the defective portion regardless of any defects on the surface of the film, so that insulation breakdown of the film caused by such defects can be suppressed and the effect of improving the insulation breakdown voltage can be enhanced can do. In addition, even if insulation breakdown occurs, the coating layer having a small surface energy is peeled from the film and only the coating layer is destroyed and the film is not destroyed, thereby preventing short-circuiting and improving the effect of improving the breakdown voltage have.

Example

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The various characteristic values in the examples were measured and evaluated by the following methods.

(1) Average particle size and mouth ratio of particles

(1-1) Average particle size and mouth ratio of powder

On the sample stand, the powder was scattered so that individual particles did not overlap as much as possible, and a gold thin film deposition layer was formed on the surface by a gold sputtering apparatus to a thickness of 200 to 300 ANGSTROM. Subsequently, observation was made at 10,000 to 30,000 times using a scanning electron microscope, and particle diameters (Di), long diameters (Dli) and short diameters Dsi) was obtained.

(1-2) Average particle size and mouth ratio of particles in the film

A piece of the sample film was fixed on a sample table for a scanning electron microscope, and the surface of the film was exposed to light under a condition of 0.25 kV, 1.25 mA under a vacuum of 0.13 Pa using a sputtering apparatus (JIS-1100 type ion sputtering apparatus) Was subjected to ion etching treatment for 10 minutes. Further, gold sputtering was carried out using the same apparatus, and observation was made at 10,000 to 30,000 times using a scanning electron microscope. The particle size (Di) of at least 1000 particles was measured with Lugex 500 manufactured by Nihon Regulator Co., , Long diameter (Dli) and short diameter (Dsi) were obtained.

With respect to the average particle diameter and the particle diameter ratio of the powder, the value obtained in the above (1-2) is used for the average particle diameter and the particle diameter ratio of the particles in the film according to the item (1-1) , And the number average value of the area-equivalent particle diameters (Di) was taken as the average particle diameter (D).

The mouth ratio was calculated as Dl / Ds from the average value (Dl) of the long and short diameters obtained from the following formula and the average value (Ds) of the short diameters.

(2) Relative standard deviation of particle size of particles

With respect to the relative standard deviation of the powder, the relative standard deviation of the particles in the film (1-1) and the relative standard deviation of the particle are the particle diameters Di and the average particle diameters D ) By the following equation.

(3) Surface roughness of film

(3-1) Center line average surface roughness (Ra)

(Lx) 1 mm, sampling pitch 2 탆, cutoff 0.25 ㎜, thickness direction enlargement using a semiconductor laser with a wavelength of 780 nm and a light probe with a beam diameter of 1.6 탆 using a non-contact type three-dimensional illuminometer (ET-30HK manufactured by Kosaka Laboratory) The projecting profile of the film surface is measured under the conditions of a magnification of 10,000 times, a transverse magnification of 200 times, and a scanning line of 100 (thus, a measurement length Ly in the Y direction = 0.2 mm). When the roughness surface is represented by Z = f (x, y), the value obtained by the following equation is defined as the centerline average surface roughness (Ra, unit: nm) of the film.

(4) Heat shrinkage

(Longitudinal direction and transverse direction) (unit:%) of the film in an atmosphere of 200 deg. C for 10 minutes in an unarmed state was obtained.

(5) Refractive index

Was measured at 23 deg. C and 65% RH using an Abbe refractometer having a sodium D line (589 nm) as a light source to obtain a refractive index (nZ) in the thickness direction.

(6) Breakdown voltage (BDV)

And measured according to the method shown in JIS C2151. The upper electrode was a cylinder made of brass having a diameter of 25 mm and the lower electrode was made of an aluminum cylinder having a diameter of 75 mm in an atmosphere at 23 캜 and 50% relative humidity using a DC withstanding voltage tester. And the voltage (unit: V) when the film was broken and short-circuited was read. The obtained voltage was divided by the film thickness (unit: 占 퐉) to obtain an insulation breakdown voltage (unit: V / 占 퐉). The measurement was carried out at 41 points, except for the larger 10 points and the smaller 10 points, and the median value of the remaining 21 points was taken as the measured value of the breakdown voltage.

The measurement at 120 占 폚 was carried out in the same manner as described above, by setting electrodes and samples in a hot air oven, connecting them to a power source with a heat-resistant cord, and starting a boosting operation 1 minute after the oven was turned on.

(7) Extensibility

The number of times that breakage occurred during the production of the 100,000 m film of the biaxially stretched film was judged as follows.

Elongation ◎: per film production of 100,000 m, breakage less than 1

Stretchability ○: per membrane production of 100,000 m, breakage is less than 1 ~ 2 times

Degradability [Delta]: Per film production of 100,000 m, breakage is less than 2 times to 4 times

Degradability X: Per film production of 100,000 m, breakage is less than 4 times to less than 8 times

Extensibility xx: Per film production of 100,000 m, breaking at least 8 times

(8) Wettability

In the production process of the film, the film was rolled at a speed of 140 m / min on a roll of 9000 m in a width of 500 mm, and the wound state of the obtained roll and the sectional deviation in the roll section were classified as follows.

[Wounded figure]

A: There is no pimples on the surface of the roll, and the wound is good.

B: On the surface of the roll, there are one or more than four pimples (protuberance bumps), and the wound is almost fine.

C: There are less than 10 pimples on the surface of the roll (protruding bumps), and the wound is slightly bad, but can be used as a product.

D: There are more than 10 pimples on the surface of the roll (protruding bumps).

[Cross section]

?: Good cross-sectional deviation of less than 0.5 mm on the roll section.

?: Almost good, with 0.5 mm or more and less than 1 mm in cross section on the roll section.

?: The product can be used as a product although the cross-section deviation at the cross section of the roll is 1 mm or more and less than 2 mm and slightly decreased.

X: The cross-section deviation in the cross section of the roll is 2 mm or more, so that it can not be used as a product.

Xx: The section deviation becomes large while rolling the roll, and a roll of 9000 m can not be produced.

(9) Pyrolysis temperature

(TG / DTA220, manufactured by Seiko Electronics Industry Co., Ltd.) at the rate of temperature increase of 10 DEG C / minute, and the temperature Was determined by the tangential method to obtain the thermal decomposition temperature (unit: 占 폚).

(10) Glass transition temperature and melting point

A sample of about 20 mg was placed in a pan for measurement and mounted on a differential scanning calorimeter (DSC) (DSCQ100, manufactured by TA Instruments), and the temperature was raised from room temperature (25 캜) to 280 캜 at a rate of 20 캜 / The melting point was measured, and after the sample was quenched, the glass transition temperature (unit: 占 폚) was measured by raising the temperature again at a rate of 20 占 폚 / min.

(11) The storage elastic modulus (E '), the loss elastic modulus (E'), the dielectric tangent (tan delta)

(E ') of the film sample under the condition of a vibration frequency of 10 Hz while raising the temperature from 25 ° C to 230 ° C at a rate of 2 ° C / minute using a dynamic viscoelasticity measuring apparatus (DDV-01FP, (Unit: MPa) and the loss elastic modulus (E ") (unit: MPa) were measured in the same manner as in Example 1. At this time, the sample length was 4 cm in the measuring direction x 3 mm in the width direction The peak temperature (unit: DEG C) of the elastic modulus (E ") and the storage elastic modulus (E ') at 120 DEG C (unit: MPa). Measurements were made for each of the longitudinal direction and the transverse direction of the film, and their average values were calculated.

The dielectric loss tangent (tan?) Was determined by measuring the dielectric loss tester (TR-10C) manufactured by Ando Electric Co., Ltd. under conditions of a temperature of 120 ° C and a vibration frequency of 1 kHz. A sample was prepared in accordance with JIS C2151. Measurements were made for each of the longitudinal direction and the transverse direction of the film, and their average values were calculated.

Example 1

The weight average molecular weight of 3.0 × 10 ^5, and the almost complete syndiotactic structure is a, the polymer Y with polystyrene, 67.5 parts by weight is observed, the intrinsic viscosity measured in chloroform 0.32 ㎗ / g of polyester in ¹³ C-NMR measurement (2 (30% by mass in 100% by mass of the resultant film), 30% by mass of the resulting film, (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX1010, manufactured by Ciba Specialty Chemicals Inc., melting point 120 (2.0% by mass in 100% by mass of the resulting film) and a spherical silicone resin particle having an average particle diameter of 0.3 占 퐉, a relative standard deviation of 0.15 and an aspect ratio of 1.10 0.5 parts by mass (the resulting film 10 0.5 mass% in 0 mass%) were blended to obtain a resin composition.

The obtained resin composition was dried at 120 DEG C for 7 hours, then fed to an extruder, melted at 290 DEG C, extruded from a die slit, and then cooled and solidified on a casting drum cooled to 50 DEG C to prepare an unoriented sheet.

This unstretched sheet was stretched 3.1 times in the longitudinal direction (machine direction) at 140 DEG C, and subsequently in the tenter, and then stretched 3.4 times in the transverse direction (direction perpendicular to the machine axis direction and thickness direction). At that time, the stretching speed in the transverse direction was set to 5000% / min. The stretching temperature in the transverse direction was 126 占 폚 for the first stage and 145 占 폚 for the final stage. Thereafter, the film was heat-set at 240 DEG C for 9 seconds, and while it was cooled to 180 DEG C, 4% relaxation treatment was performed in the transverse direction to obtain a biaxially oriented film having a thickness of 3.0 mu m. Table 1 shows the properties of the obtained film.

Comparative Examples 1 to 5

A biaxially oriented film having a thickness of 3.0 占 퐉 was formed in the same manner as in Example 1 except that the content of PPE as Polymer Y, the content of the antioxidant, and the film production conditions were changed as shown in Table 1, Table 1 shows the properties of the obtained film. The amount of polystyrene was adjusted in accordance with the increase or decrease in the content of the polymer Y and the antioxidant so that the total amount was 100 parts by mass.

According to Example 1 and Comparative Examples 1 to 5, it is possible to obtain knowledge related to PPE as the polymer Y, presence or absence of the antioxidant, and the content.

The films obtained in Example 1 and Comparative Example 4 in which the content of the polymer Y (PPE) and the antioxidant are appropriate have good stretchability and winding property, have a high dielectric breakdown voltage, and are preferable as insulators for capacitors for hybrid vehicles and the like .

The film obtained in Comparative Example 5 had a slightly poor stretchability and winding property.

Also, in Comparative Example 3, the content of the polymer Y (PPE) was excessively large, thereby leading to unstable polymer sea-island structure, poor stretchability, easy breakage in a tenter or the like at the time of film production, Although a cut sheet sample can be taken, it is difficult to take a long roll sample, and the thickness irregularity is also poor, so that the obtained film can not withstand use as an insulator of a capacitor.

Comparative Example 6

Except that 30 mass% of a polycarbonate having a melt viscosity of 150 Pa 占 퐏 at 280 占 폚 and a glass transition temperature Tg of 145 占 폚 was used as the polymer Y and the film production conditions were as shown in Table 2, In the same manner, a biaxially oriented film having a thickness of 3.0 占 퐉 was obtained and wound in a rolled form. Table 2 shows the properties of the obtained film.

Example 5

(Trade name: IRGANOX1024, melting point: 210 占 폚, pyrolysis temperature: 30 占 폚, manufactured by Ciba Specialty Chemicals, Inc.) as an antioxidant, N, N'-bis [3- (3,5- 275 占 폚, C2) was used in the same manner as in Example 1, and a biaxially stretched film having a thickness of 3.0 占 퐉 was obtained and wound in a rolled form. Table 2 shows the properties of the obtained film.

Example 6

Except that 67.5 parts by mass of polystyrene and 0.5 part by mass of spherical silicone resin particles having an average particle size of 0.5 占 퐉, a relative standard deviation of 0.15 and an particle size ratio of 1.08 as inert fine particles A (0.5 mass% in 100 mass% of the resulting film) , A biaxially stretched film having a thickness of 3.0 탆 was obtained in the same manner as in Example 1, and the film was wound in a rolled form. Table 2 shows the properties of the obtained film.

Examples 7 to 9

A biaxially oriented film having a thickness of 3.0 탆 was obtained in the same manner as in Example 6 except that the spherical silicone resin particles as the inert fine particles A had an average particle diameter, relative standard deviation, an aspect ratio, and a content as shown in Table 2, . Table 2 shows the properties of the obtained film. Further, the amount of the polystyrene was adjusted in accordance with the increase or decrease of the content of the inactive fine particles A so that the total amount was 100 parts by mass.

Example 10

0.5 part by mass (0.5 mass% in 100 mass% of the resulting film) of spherical silicone resin particles having an average particle diameter of 0.3 占 퐉, a relative standard deviation of 0.17 and an inlet ratio of 1.10 as an inert fine particle A and 67.4 parts by mass of an inert fine particle And 0.1 mass parts (0.1 mass% in 100 mass% of the obtained film) of spherical silicone resin particles having an average particle diameter of 0.5 占 퐉, a relative standard deviation of 0.15, and an aspect ratio of 1.10 were blended in the same manner as in Example 1 A biaxially oriented film having a thickness of 3.0 占 퐉 was obtained and wound in a rolled form. Table 2 shows the properties of the obtained film.

Examples 11 and 12

The relative standard deviation, the particle size ratio, the content, and the average particle diameter, relative standard deviation, particle size ratio and content of the spherical silicone resin particles as the inert fine particles A are shown in Table 2 , A biaxially oriented film having a thickness of 3.0 占 퐉 was obtained in the same manner as in Example 10 and wound up in a rolled form. Table 2 shows the properties of the obtained film. The amount of the polystyrene was adjusted in accordance with the increase or decrease in the content of the inactive fine particles A and the inactive fine particles B, so that the total amount was 100 parts by mass.

Example 13

(Same as Example 1) except that 0.3 part by mass of the spherical silicone resin particles having an average particle diameter of 1.3 占 퐉, a relative standard deviation of 0.14 and an inlet ratio of 1.10 as inert fine particles A (100 mass% of the resulting film was 0.3 mass% To give a biaxially stretched film having a thickness of 3.0 탆, and the film was wound in a rolled form. Table 2 shows the properties of the obtained film.

According to Example 1 and Examples 6 to 13, knowledge related to aspects of the inactive fine particles A and the inactive fine particles B can be obtained.

The films obtained in Examples 1 and 6 to 13, in which the mode of the inert fine particles contained were appropriate, were all excellent in stretchability and winding property and high in dielectric breakdown voltage, and therefore preferred as an insulator of a capacitor.

Using the obtained film, a capacitor was produced as follows.

First, aluminum was vacuum deposited on one side of the film to a thickness of 500 Å. At this time, a vertical stripe was formed by repeating a deposition portion of 8 mm width and a non-deposition portion of 1 mm width. The obtained evaporated film was slit at the central portion in the width direction of each of the evaporated portion and non-evaporated portion, and wound up on a tape having a width of 4.5 mm and made of a vapor-deposited portion having a width of 4 mm and a non-vapor-deposited portion having a width of 0.5 mm. Subsequently, the two reels were superimposed on each other so that the non-vapor-deposited portions had the cross-section on the opposite side, respectively, and wound to obtain a rolled body, which was then pressed at 150 DEG C and 1 MPa for 5 minutes. Metallicon was sprayed on both end faces of the wound body after pressing to form an external electrode, and a lead wire was welded to the metallic wire to prepare a wound film capacitor.

The film capacitors using the films obtained in Examples 1, 5 to 13 and Comparative Examples 4 and 5 were excellent in heat resistance and withstand voltage characteristics (dielectric breakdown voltage (BDV)) and excellent performance as a capacitor. And was excellent in workability in the production of a capacitor. Particularly, the film capacitor using the film obtained in Example 1 was particularly excellent in withstanding voltage characteristics and exhibited superior performance as a capacitor.

Effects of the Invention

According to the present invention, a high-insulating film excellent in electrical characteristics, heat resistance, and handling properties can be obtained. In particular, a highly insulating film having a high dielectric breakdown voltage can be obtained. In addition, a highly insulating film having a high dielectric breakdown voltage can be obtained even at a high temperature. Therefore, the high-insulating film obtained by the present invention can be preferably used as an insulator of a capacitor. In particular, it can be preferably used as an insulator of a higher performance capacitor such as a capacitor mounted on a hybrid car or the like.

Industrial availability

The high-insulating film of the present invention can be preferably used as an insulator of a capacitor. In particular, it can be preferably used as an insulator of a capacitor which is exposed to a relatively high temperature environment mounted on a hybrid car or the like.

Claims (15)

A biaxially stretched film comprising a styrenic polymer having a syndyotactic structure in an amount of more than 50 mass% based on the mass of the biaxially oriented film, wherein the average particle diameter is 0.05 占 퐉 or more and 1.5 占 퐉 or less and the relative standard deviation of the particle diameter is 0.5 Of the total amount of the inert fine particles A, 0.05 to 2.0 mass% of the inert fine particles A, 0.1 to 8 mass% of the antioxidant, 11 to 48 mass% of the polymer Y having a glass transition temperature Tg of 130 deg. , The polymer Y is a polyphenylene ether represented by the following formula,

Wherein the content ratio of the polymer Y to the antioxidant (content of the polymer Y / content of the antioxidant) is 1 to 100 and the refractive index in the thickness direction is 1.5750 or more and 1.6040 or less based on the weight of the high insulating film. The method according to claim 1,
Wherein a peak temperature peak of a loss elastic modulus (E ") measured at a vibration frequency of 10 Hz is 120 DEG C or more and 150 DEG C or less and a dielectric loss tangent (tan?) At 120 DEG C and a frequency of 1 kHz is 0.0015 or less. The method according to claim 1,
And a heat shrinkage rate in the longitudinal and transverse directions of 200 DEG C x 10 minutes is 6% or less. The method according to claim 1,
And a dielectric breakdown voltage (BDV) at 120 占 폚 of 350 V / 占 퐉 or more. The method according to claim 1,
A high dielectric constant film having a storage modulus (E ') of 600 MPa or more at 120 DEG C measured at a vibration frequency of 10 Hz by dynamic viscoelasticity measurement. The method according to claim 1,
A high insulating film having a film thickness of 0.4 탆 or more and less than 6.5 탆. The method according to claim 1,
And an inert fine particle B having an average particle diameter of not less than 0.5 mu m and not more than 3.0 mu m and having an average particle diameter of not less than 0.2 mu m larger than the average particle diameter of the inert fine particles A and a relative standard deviation of the particle diameter of not more than 0.5, Insulating film. The method according to claim 1,
Wherein the inert fine particles A are spherical particles having an aspect ratio of 1.0 or more and 1.3 or less. 9. The method of claim 8,
Wherein the inert fine particle (A) is a spherical polymer resin particle. 9. The method of claim 8,
Wherein the inert fine particles (A) are spherical silicone resin particles. 8. The method of claim 7,
Wherein the inert fine particles B are spherical polymer resin particles having an aspect ratio of 1.0 or more and 1.3 or less. The method according to claim 1,
A high dielectric film having a pyrolysis temperature of 250 DEG C or higher. 13. A capacitor using the high-insulating film according to any one of claims 1 to 12. delete delete